Interlock systems are known for use in connection with steering column-mounted ignition switch mechanisms for preventing the ignition lock from being placed in the "Lock" position unless the transmission shift selector has been moved to the "Park" position. For example, U.S. Pat. No. 4,520,640 describes a mechanical interlock system including a slidable ignition pin, a transmission selector pin and a latch ball therebetween to prevent actuation of the ignition switch to the "Lock" position unless the transmission selector has been moved to the "Park" position.
U.S. Pat. No. 4,232,538 also discloses a mechanical interlock system for carrying out the same interlocking function.
One particular mechanical ignition interlock system includes a pivotable locking lever operably connected to the transmission selector via a cable. When the transmission selector is not in the "Park" position, the cable positions the locking lever in a recess of an ignition slide to prevent movement of the ignition switch from the "Off" position to the "Lock" position. When the transmission selector is finally moved to the "Park" position, the cable pivots the locking lever out of the recess to free the ignition slide and thus the ignition switch for movement from the "Off" position to the "Lock" position.
Interlock systems are also known for use in connection with the ignition switch and the transmission selector to prevent shifting of the transmission selector from the "Park" position until the ignition switch has been moved from the "Lock" position to the "Start" or "Run" position. Copending U.S. application Ser. Nos. 137,759, now U.S. Pat. No. 4,936,158, and 314,717, now U.S. Pat. No. 5,018,610, of common assignee herewith disclose interlock systems of the mechanical and electromechanical type to carry out this interlock function between the ignition switch and the transmission selector.
It is an object of the invention to provide an improved ignition interlock mechanism for a motor vehicle to prevent movement of the ignition switch from the "Off" position to the "Lock" position unless the transmission selector has been moved to the "Park" position.
It is another object of the invention to provide an improved electromechanical ignition interlock mechanism which eliminates the need for a cable to actuate the locking lever.
It is another object of the invention to provide an improved electromechanical ignition interlock mechanism which is responsive to certain input signals representative of the status of the transmission selector and the ignition key in/out.
It is still another object of the invention to provide an improved electromechanical ignition interlock mechanism which is low in cost and reliable in operation without interfering with operation of existing components of the vehicle.